And because *x^x* means *x xor x* which numeric value is *0* or *1* so the derivative is equal to zero.
*Christophe BAL* *Enseignant de mathématiques en Lycée **et développeur Python amateur* *---* *French math teacher in a "Lycée" **and **Python **amateur developer* -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at http://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAAb4jG%3DudR3U3EG2VDUW5qdAG5TEo8HBxTDWc8f3_4f9a20Vjw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.